Note 21 - Quarterly Financial Data (unaudited) (Details) - Selected Unaudited Quarterly Financial Data (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly operating data:
Interest income	$ 50,294	$ 49,851	$ 50,295	$ 50,086	$ 51,722	$ 53,193	$ 54,384	$ 54,415	$ 200,526	$ 213,714	$ 224,498
Interest expense	13,058	12,866	12,999	15,940	14,498	15,610	16,097	17,070	54,863	63,275	76,723
Net interest income	37,236	36,985	37,296	34,146	37,224	37,583	38,287	37,345	145,663	150,439	147,775
Provision for loan losses	1,000	3,435	3,500	6,000	5,000	5,000	5,000	6,000	13,935	21,000	21,500
Other operating income	1,064	945	2,199	5,348	2,566	3,513	1,108	1,878	1,586	1,413	1,477
Other operating expense	18,894	19,050	20,213	22,419	19,808	20,743	20,239	21,536	80,576	82,326	77,739
Income before income
tax expense	18,406	15,445	15,782	11,075	14,982	15,353	14,156	11,687	60,708	56,178	58,817
Income tax expense	6,458	6,024	6,155	4,319	5,782	5,988	5,519	4,558	22,956	21,847	23,469
Net income	$ 11,948	$ 9,421	$ 9,627	$ 6,756	$ 9,200	$ 9,365	$ 8,637	$ 7,129	$ 37,752	$ 34,331	$ 35,348
Basic earnings per common share (in Dollars per share)	$ 0.40	$ 0.32	$ 0.32	$ 0.22	$ 0.30	$ 0.31	$ 0.28	$ 0.23	$ 1.26	$ 1.13	$ 1.15
Diluted earnings per common share (in Dollars per share)	$ 0.40	$ 0.32	$ 0.32	$ 0.22	$ 0.30	$ 0.31	$ 0.28	$ 0.23	$ 1.26	$ 1.13	$ 1.15
Dividends per common share (in Dollars per share)	$ 0.13	$ 0.13	$ 0.13	$ 0.13	$ 0.13	$ 0.13	$ 0.13	$ 0.13
Average common shares outstanding for:
Basic earnings per share (in Shares)	29,762	29,773	30,213	30,449	30,310	30,432	30,472	30,396	30,047	30,402	30,623
Diluted earnings per share (in Shares)	29,802	29,805	30,235	30,481	30,340	30,462	30,492	30,420	30,073	30,433	30,654